Automatic cut-off-valve gear



(No Model.)

G. DANBY..

AUTOMATIC OUT-OFF VALVE GEAR.

No. 317,979. Patented May 19, 1885.

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AUTOMATIC CUT-O'FF-VALVE GEAR.

SPECIFICATION forming part of Letters Patent No. 317,979, dated May19,1885.

Application filed December 24, 1884.

To all whom, it may concern:

Be it known that I, GEORGE DANBY, a citizen of the United States,residing at Mount Holly, in the county of Olermont and State of Ohio,have invented certain new and useful Improvements in AutomaticOut-Offs,of which the following is a specification, reference being hadtherein to the accompanying drawings.

My invention includes a novel combination of devices, wherewith the mainvalve of an engine can be automatically controlled for the purpose ofadmitting a greater or less volume of steam into the cylinder, andthereby regulating the speed of the piston to suit any special duty. Themain valve may be of the or dinary slide pattern, or it may be adaptedto have a reciprocating rotary motion within the steam-chest, and ispreferably operated by a rock -shaft whose outer end carries an arm thatvibrates or swings alongside the steam cylinder, this motion of said armbeing effected by a rod that is driven either by a cam or eccentricsecured to the engine-shaft in the usual manner.

The method of coupling the eccentric-rod to the rock-shaft arm isimmaterial; but said coupling must be of such a character as to becapable of being either raised or lowered for the purpose of regulatingthe swing of said arm, and thereby controlling the stroke of the mainvalve. The elevation and depression of this coupled end of theeccentric-rod is ac complished by any approved form of governor, whichlatter is driven from the engine shaft, either by a belt or gearing, orotherwise. When the engine runs too fast, the governor automaticallydepresses the coupled end of the eccentric-rod, thereby limiting theswing of the rock-shaft arm and restricting the travel of the mainvalve, which act reduces the volume of steam that enters the cylinderand diminishes the piston-speed; but if the engine should run too slowthe opposite action takes place-that is to say, the governor nowautomatically elevates the coupled end of the cocentric-rod,therebycompelling the rockshaft arm to swing a greater distance and effect acorresponding increase in the travel of the main valve. Consequently agreater volume of steam will be admitted into the cylinder and thepiston-speed increased accordingly, as hereinafter more fully described.

the sensitiveness of the governor.

(No model.)

Applied to the engine is a fulcrumed lever, one end of said leverhavingthe governor-rod i coupled thereto,whilc its opposite end carries aweight capable of being shifted by hand and retained at any specificadjustment-,the object of this weight being to counterbalance theconnected portion of the eccentric-rod and its accessories, and also toincrease or diminish By retracting this counter-balance toward thefulcrum of the lever the governor will have less duty to perform, andwill act quite promptly, while the advancement of said weight willincrease the load imposed on the governor and cause it to operate moreslowly, as hereinafter more fully described.

vIn the annexed drawings, Figure 1 is a side elevation of a steam-engineprovided with my automatic out-off. Fig. 2 is a vertical section of thesteam-chest. Fig. 3 is an enlarged vertical section of the coupling thatactuates the rock-shaft arm. Figs. 4 and 5 are respectively a sideelevation and horizontal section of a modification of said coupling.

A represents a steam-cylinder whose chest B incloses an ordinaryslidevalve, C, which latter is adapted to communicate with theinlet-ports D D and exhaust-port E in the usual manner. Valve 0 iscoupled by a link, X, to an internal crank or cam, F, of a rock-shaft,G, said shaft being disposed transversely of ing arm,H, depending fromits outer end. The

lower or free end of this arm traverses a slot in the block I, as seenin Fig. 3,to which block is attached one end of the eccentric-rodJ,previously alluded to. Furthermore, this block I has connected to itthe lower end of a rod, K, the .upper end thereof being suspended from alever, L, that is fulcruined at M to a standard or other supportprojecting rigidly from the main frame of the engine. One end of thislever carries a counter-balance, N, capable of being adjusted by aset-screw,0, that engages therewith, the opposite end of said leverhaving attached to it the rod P of any suitable form of governor, R, thelatter being driven by the engine in the customary manner.

The operation of my automatic cutoff is as follows: The weight N isfirst adjusted so as toexactly counterbalance the rods J K when ICO theballs of the governor R are in their normal or closed condition, andsaid weight is then shifted farther away from the fulcrum M, in case itis desired to prevent any action of said governor until aheavy duty isimposed on the engine. The engine being then started, the eccentric-rodJ imparts motion to the arm H, thereby vibrating or swinging the latterand causing the slide-valve O to reciprocate within the steam-chest inthe usual manner;

. but if the engine should run so fast as to cause the centrifugal forceof the governor-balls to overcome the weight of counter-balance N therod P would be forced down, thereby swinging the lever L on its fulcrumM and depressing the rod K and coupling-block I. Itis evident the motionof eccentric-rod J will now impart a comparatively limited swing to thearm H,because the block I is located near the free end of said arm.Hence the stroke of the valve 0 is restricted and less steam is admittedto the cylinder; but if the engine should run too slow the governorballs will drop, thereby elevating the rods P K, which act pulls thecoupling-block I toward the rockshaft G and imparts a longer stroke tothe main valve 0. This increased stroke uncovers more fully theinlet-ports D D and allows a greater volume of steam to enter thecylinder and drive the piston at a higher speed. The cause of thisincreased stroke of the valve will be apparent when it is consideredthat the motion of the eccentric-rod is at all times the same. Thereforeit is evident that the elevation of the free end of said rod must causean increased swing of the arm H and its attached rock-shaft G.

In the modification of my invention seen in Figs. 4 and 5 the swingingarm H is slotted longitudinally at S to receive a sliding block, T,whichblock carries a short stud, U. This stud couples the rod K and theforked end V of the eccentric-rod J to said block T. Furthermore, it ispreferred to curve the arm H, as indicated by the dotted lines in Fig.4, and if this is done it is evident the slot S must have acorresponding shape imparted to it. Finally, the rod K may be attachedto the mid-length of block I, as seen in Fig. 1, or to the end of saidblock, as represented in Fig. 3. I claim as my invention Thecombination, in a steam-engine, of a rockshaft, G, actuating the mainvalve, an

eccentric-rod, J, connected by a couplingblock, I, to the arm H, and agovernor-rod, P, communicating with said eccentric-rod and also with thefulcrumed lever L, which latter carries a shiftable counter-balance, N,that is capable of being retained at any specific adjustment, for thepurpose herein described.

In testimony whereof I affix my signature in presence of two witnesses.

GEORGE DANBY. Witnesses: JAMES H. LAYMAN, WM. DANBY.

